Before I started diving into it, I thought I would bounce this off the experts...

I picked up a 2008 KTM 990 Adventure S recently and have hit reserve twice thus far. Both times, the bike seemed to be starving for fuel while the reserve light was on.

For instance, it would hesitate under acceleration, especially above 5,000 RPM, and pop noticeably while decelerating. My KTM 525 does the same thing just as I need to switch the petcock over to reserve.

To me, this suggests that either the tanks are not vented properly or fuel isn’t getting from the right tank fast enough even though both petcocks are open. If it were the fuel filter, I would expect fuel starvation regardless of fuel level. If it is tank venting problem, I would expect starvation to get progressly worse as fuel level in the tanks dropped due to the greater air volume.

When I opened the gas caps at the gas station, I didn’t hear any in-rush of air, but there was a noisy diesel truck idling nearby so I may have just missed it. After refueling, the bike again ran the same as it did before hitting reserve (i.e., no hesitation while accelerating, no popping on decal).

This bike has the canister, SAS and servo controlled butterflies removed. It has Akros and I’m told the Akro map loaded; however, I don’t know which particular Akro is loaded.

Hi, I just did a 4000 mile ride on my 990 last week, I went from ATL GA into Moab Utah and back to ATL in 9 days. While on my ride my brother had this exact problem. He also has a 990, he would burn about 100 miles of gas and it would start to play up. Anything over half throttle at about 5000 rpm and the bike would hold up, hesitate, pop and crackle badly on deceleration and be a general pain in the arse, it seems the weight of the fuel on full tanks was enough to push the fuel past the crap in the filters even with a pressurized system it still needed the weight of all that fuel in a full tanks to work properly.

When we got back into town on Sunday we rested but on Monday he pulled it apart to find his fuel filters where shot. He took the filters to the local KTM dealer and they also confirmed the filters where well shot and needed replacing.

I am the said brother form Jhalls. Fuel Filters are 100% problem. They'll cost you $120 for the replacement kit (three (3) filters.

What happens under low fuel, above 5K RPM and more thna 50% throttle with blocked filters the pump can't pull the required fuel through quick enough. One of the side effects is the fuel begins to boil...

When you fill up, you'll add cold fuel, stopping the boiling, and the heat coming into the left tank isn't enough to boil 3 gallons but is enough to boil 1 gallon.

The surging you feel is caviatation of boiling fuel going through the pump.

Whilethe tank is off, buy soem self-adhesive heat shield (KTM actually make a sheet of the stuff for the dirt bike that is self adhesive and enough material to cover your entire bike) for $25.

Englishmatt is 105% accurate here. I've had the same symptoms in the same situation, with the same resolution. Fuel heat, blocked filter, pump cavitation and hesitation.

Quote:

Originally Posted by Englishmatt

I am the said brother form Jhalls. Fuel Filters are 100% problem. They'll cost you $120 for the replacement kit (three (3) filters.

What happens under low fuel, above 5K RPM and more thna 50% throttle with blocked filters the pump can't pull the required fuel through quick enough. One of the side effects is the fuel begins to boil...

When you fill up, you'll add cold fuel, stopping the boiling, and the heat coming into the left tank isn't enough to boil 3 gallons but is enough to boil 1 gallon.

The surging you feel is caviatation of boiling fuel going through the pump.

Whilethe tank is off, buy soem self-adhesive heat shield (KTM actually make a sheet of the stuff for the dirt bike that is self adhesive and enough material to cover your entire bike) for $25.

If I had a 990 / fuel pump in the tank, I would keep the Gas Level up at least above 1/4 Tank as much as possible, Especially during the Summer,
to keep the Heat Stress off the Fuel Pump. This will also help keep the debris out of your Fuel Filter.

If I had a 990 / fuel pump in the tank, I would keep the Gas Level up at least above 1/4 Tank as much as possible, Especially during the Summer,
to keep the Heat Stress off the Fuel Pump. This will also help keep the debris out of your Fuel Filter.

This will be a side benefit of the advtank rear tank I'm in the process of adding.

What makes it $120 is there are actually three (3) filters in the Fuel Pump.

1.) Normal looking Fuel Filter in the Regulator Valve
2.) Sock/Screen Filter that it outside of the fuel pump enclosure
3.) Very small interla filter/screen that goes from the fuel pump to the regulator valve.

Oh, and "keeping the fuel above 1/4 tank in the summer" is a laughable solution/suggestion. In theory, it's ok....but when you pay top dollar for this bike, there's principalities involved smokey!

This is an Adventure bike. The V-Strom already easts this thing up for fuel economy. Stopping every 100 miles to keep the tanks topped off, to avoid the bike quitting due to a dodgy fuel pump is simply not a workable solution.

So it's an all inclusive filter kit, no additional seals need to complete the job correct?

Quote:

Originally Posted by Englishmatt

What makes it $120 is there are actually three (3) filters in the Fuel Pump.

1.) Normal looking Fuel Filter in the Regulator Valve
2.) Sock/Screen Filter that it outside of the fuel pump enclosure
3.) Very small interla filter/screen that goes from the fuel pump to the regulator valve.